The invention relates to an apparatus for beading a cup edge and is particularly useful for forming the rim of a cup having a seamed annular sidewall and a polygonal base.
It has previously been known to provide a cylindrical container with a beaded rim by grasping the container sidewall and holding it against a bead forming spinning head. Typically the grasping has been by means of two parallel opposed gripping jaws. The problem with this type of cup holding device for spin forming operations has been a potential of damage to the sidewall of the container if it is grasped too tightly between the opposing jaws or slippage when it is grasped too loosely. An example of such a typical grasping device in combination with a conventional head is shown in U.S. Pat. No. 4,204,462 to Richards, et al.
The use of star wheels for guiding, advancing and containing bottles and other containers has heretofore been common, particularly in those machines utilized for filling and capping bottles with fluid materials. The combination of star wheels to guide and confine a polygonal based cup to be beaded by a spinning operation with a complementary polygonal socket to prevent cup rotation is believed novel, however.